To date, resonance devices that employ the MEMS (Micro Electro Mechanical Systems) technique are used, for example, as timing devices. In general, such resonance devices are mounted on a printed board embedded in an electronic device, such as a smartphone. The resonance devices include a lower side substrate, an upper side substrate that, together with the lower side substrate, forms a cavity therebetween, and a resonator disposed within the cavity between the lower side substrate and the upper side substrate.
For example, Patent Document 1 (identified below) discloses an out-of-plane flexural resonator that includes a plurality of vibration arms. In this resonator, the vibration arms are connected at fixed ends thereof to a front end of a base portion, and the base portion is connected at a rear end thereof on a side opposite to the front end to a support portion. The support portion is connected, for example, to a base stage sandwiched between the lower side substrate and the upper side substrate. In the example illustrated in FIG. 1 of Patent Document 1, the electric fields applied to the vibration arms are set to be oriented in mutually opposite directions, and thus vibrations of mutually opposite phases are achieved between the vibration arm in an inner side portion and the two vibration arms in an outer side portion.
Patent Document 1: Japanese Patent No. 5071058.